diff --git a/Makefile b/Makefile
index fb1122ca..08abfa12 100644
--- a/Makefile
+++ b/Makefile
@@ -48,7 +48,7 @@ clean: tidy
 	find gfx \( -iname '*.1bpp' -o -iname '*.2bpp' -o -iname '*.pic' \) -delete
 
 tidy:
-	rm -f $(roms) $(pokered_obj) $(pokeblue_obj) $(pokeblue_debug_obj) $(roms:.gbc=.map) $(roms:.gbc=.sym) rgbdscheck.o
+	$(RM) $(roms) $(pokered_obj) $(pokeblue_obj) $(pokeblue_debug_obj) $(roms:.gbc=.map) $(roms:.gbc=.sym) rgbdscheck.o
 	$(MAKE) clean -C tools/
 
 compare: $(roms)
diff --git a/tools/Makefile b/tools/Makefile
index 7ab1d146..32f764a1 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -1,16 +1,21 @@
 .PHONY: all clean
 
 CC := gcc
-CFLAGS := -O3 -std=c99 -Wall -Wextra -Wno-missing-field-initializers
+CFLAGS := -O3 -std=c11 -Wall -Wextra -pedantic -Wno-missing-field-initializers
 
-tools := scan_includes gfx pkmncompress
+tools := \
+	gfx \
+	pkmncompress \
+	scan_includes
 
 all: $(tools)
 	@:
 
 clean:
-	rm -f $(tools)
+	$(RM) $(tools)
 
 gfx: common.h
+scan_includes: common.h
+
 %: %.c
 	$(CC) $(CFLAGS) -o $@ $<
diff --git a/tools/common.h b/tools/common.h
index 4da0b2ef..a8b69445 100644
--- a/tools/common.h
+++ b/tools/common.h
@@ -1,40 +1,132 @@
 #ifndef GUARD_COMMON_H
 #define GUARD_COMMON_H
 
-int __getopt_long_i__;
-#define getopt_long(c, v, s, l) getopt_long(c, v, s, l, &__getopt_long_i__)
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <inttypes.h>
+#include <string.h>
+#include <errno.h>
+#include <getopt.h>
 
-FILE *fopen_verbose(char *filename, char *mode) {
+#ifndef PROGRAM_NAME
+#error Define PROGRAM_NAME before including common.h!
+#endif
+#ifndef USAGE_OPTS
+#error Define USAGE_OPTS before including common.h!
+#endif
+
+#define error_exit(...) exit((fprintf(stderr, PROGRAM_NAME ": " __VA_ARGS__), 1))
+
+void usage_exit(int status) {
+	fprintf(stderr, "Usage: " PROGRAM_NAME " " USAGE_OPTS "\n");
+	exit(status);
+}
+
+int getopt_long_index;
+#define getopt_long(argc, argv, optstring, longopts) getopt_long(argc, argv, optstring, longopts, &getopt_long_index)
+
+void *xmalloc(size_t size) {
+	errno = 0;
+	void *m = malloc(size);
+	if (!m) {
+		error_exit("Could not allocate %zu bytes: %s\n", size, strerror(errno));
+	}
+	return m;
+}
+
+void *xcalloc(size_t size) {
+	errno = 0;
+	void *m = calloc(size, 1);
+	if (!m) {
+		error_exit("Could not allocate %zu bytes: %s\n", size, strerror(errno));
+	}
+	return m;
+}
+
+void *xrealloc(void *m, size_t size) {
+	errno = 0;
+	m = realloc(m, size);
+	if (!m) {
+		error_exit("Could not allocate %zu bytes: %s\n", size, strerror(errno));
+	}
+	return m;
+}
+
+FILE *xfopen(const char *filename, char rw) {
+	char mode[3] = {rw, 'b', '\0'};
+	errno = 0;
 	FILE *f = fopen(filename, mode);
 	if (!f) {
-		fprintf(stderr, "Could not open file: \"%s\"\n", filename);
+		error_exit("Could not open file \"%s\": %s\n", filename, strerror(errno));
 	}
 	return f;
 }
 
-uint8_t *read_u8(char *filename, int *size) {
-	FILE *f = fopen_verbose(filename, "rb");
-	if (!f) {
-		exit(1);
+void xfread(uint8_t *data, size_t size, const char *filename, FILE *f) {
+	errno = 0;
+	if (fread(data, 1, size, f) != size) {
+		fclose(f);
+		error_exit("Could not read from file \"%s\": %s\n", filename, strerror(errno));
 	}
-	fseek(f, 0, SEEK_END);
-	*size = ftell(f);
-	rewind(f);
-	uint8_t *data = malloc(*size);
-	if (*size != (int)fread(data, 1, *size, f)) {
-		fprintf(stderr, "Could not read file: \"%s\"\n", filename);
-		exit(1);
+}
+
+void xfwrite(const uint8_t *data, size_t size, const char *filename, FILE *f) {
+	errno = 0;
+	if (fwrite(data, 1, size, f) != size) {
+		fclose(f);
+		error_exit("Could not write to file \"%s\": %s\n", filename, strerror(errno));
 	}
+}
+
+long xfsize(const char *filename, FILE *f) {
+	long size = -1;
+	errno = 0;
+	if (!fseek(f, 0, SEEK_END)) {
+		size = ftell(f);
+		if (size != -1) {
+			rewind(f);
+		}
+	}
+	if (size == -1) {
+		error_exit("Could not measure file \"%s\": %s\n", filename, strerror(errno));
+	}
+	return size;
+}
+
+uint8_t *read_u8(const char *filename, long *size) {
+	FILE *f = xfopen(filename, 'r');
+	*size = xfsize(filename, f);
+	uint8_t *data = xmalloc(*size);
+	xfread(data, *size, filename, f);
 	fclose(f);
 	return data;
 }
 
-void write_u8(char *filename, uint8_t *data, int size) {
-	FILE *f = fopen_verbose(filename, "wb");
-	if (f) {
-		fwrite(data, 1, size, f);
+void write_u8(const char *filename, uint8_t *data, size_t size) {
+	FILE *f = xfopen(filename, 'w');
+	xfwrite(data, size, filename, f);
+	fclose(f);
+}
+
+uint32_t read_png_width(const char *filename) {
+	FILE *f = xfopen(filename, 'r');
+	uint8_t header[16] = {0};
+	xfread(header, sizeof(header), filename, f);
+	static uint8_t expected_header[16] = {
+		0x89, 'P', 'N', 'G', '\r', '\n', 0x1A, '\n', // signature
+		0, 0, 0, 13,                                 // IHDR chunk length
+		'I', 'H', 'D', 'R',                          // IHDR chunk type
+	};
+	if (memcmp(header, expected_header, sizeof(header))) {
 		fclose(f);
+		error_exit("Not a valid PNG file: \"%s\"\n", filename);
 	}
+	uint8_t bytes[4] = {0};
+	xfread(bytes, sizeof(bytes), filename, f);
+	fclose(f);
+	return (bytes[0] << 24) | (bytes[1] << 16) | (bytes[2] << 8) | bytes[3];
 }
 
 #endif // GUARD_COMMON_H
diff --git a/tools/gfx.c b/tools/gfx.c
index 7d6dd0ee..4264e669 100644
--- a/tools/gfx.c
+++ b/tools/gfx.c
@@ -1,94 +1,96 @@
-#include <stdio.h>
-#include <stdlib.h>
-#include <stdbool.h>
-#include <getopt.h>
-#include <string.h>
-#include <stdint.h>
+#define PROGRAM_NAME "gfx"
+#define USAGE_OPTS "[-h|--help] [--trim-whitespace] [--remove-whitespace] [--interleave] [--remove-duplicates [--keep-whitespace]] [--remove-xflip] [--remove-yflip] [--preserve indexes] [-d|--depth depth] [-p|--png filename.png] [-o|--out outfile] infile"
 
 #include "common.h"
 
-static void usage(void) {
-	fprintf(stderr, "Usage: gfx [--trim-whitespace] [--remove-whitespace] [--interleave] [--remove-duplicates [--keep-whitespace]] [--remove-xflip] [--remove-yflip] [--preserve indexes] [--png filename] [-d depth] [-h] [-o outfile] infile\n");
-}
-
-static void error(char *message) {
-	fputs(message, stderr);
-	fputs("\n", stderr);
-}
-
 struct Options {
-	int trim_whitespace;
-	int remove_whitespace;
-	int help;
-	char *outfile;
-	int depth;
-	int interleave;
-	int remove_duplicates;
-	int keep_whitespace;
-	int remove_xflip;
-	int remove_yflip;
+	bool trim_whitespace;
+	bool remove_whitespace;
+	bool interleave;
+	bool remove_duplicates;
+	bool keep_whitespace;
+	bool remove_xflip;
+	bool remove_yflip;
 	int *preserved;
 	int num_preserved;
+	int depth;
 	char *png_file;
+	char *outfile;
 };
 
-struct Options Options = {
-	.depth = 2,
-};
+struct Options options = {.depth = 2};
 
-void get_args(int argc, char *argv[]) {
+void parse_args(int argc, char *argv[]) {
 	struct option long_options[] = {
-		{"remove-whitespace", no_argument, &Options.remove_whitespace, 1},
-		{"trim-whitespace", no_argument, &Options.trim_whitespace, 1},
-		{"interleave", no_argument, &Options.interleave, 1},
-		{"remove-duplicates", no_argument, &Options.remove_duplicates, 1},
-		{"keep-whitespace", no_argument, &Options.keep_whitespace, 1},
-		{"remove-xflip", no_argument, &Options.remove_xflip, 1},
-		{"remove-yflip", no_argument, &Options.remove_yflip, 1},
+		{"remove-whitespace", no_argument, 0, 'R'},
+		{"trim-whitespace", no_argument, 0, 'T'},
+		{"interleave", no_argument, 0, 'I'},
+		{"remove-duplicates", no_argument, 0, 'D'},
+		{"keep-whitespace", no_argument, 0, 'W'},
+		{"remove-xflip", no_argument, 0, 'X'},
+		{"remove-yflip", no_argument, 0, 'Y'},
 		{"preserve", required_argument, 0, 'r'},
 		{"png", required_argument, 0, 'p'},
 		{"depth", required_argument, 0, 'd'},
+		{"out", required_argument, 0, 'o'},
 		{"help", no_argument, 0, 'h'},
 		{0}
 	};
-	char *token;
-	for (int opt = 0; opt != -1;) {
-		switch (opt = getopt_long(argc, argv, "ho:d:p:", long_options)) {
-		case 'h':
-			Options.help = true;
+	for (int opt; (opt = getopt_long(argc, argv, "d:o:p:h", long_options)) != -1;) {
+		switch (opt) {
+		case 'R':
+			options.remove_whitespace = true;
 			break;
-		case 'o':
-			Options.outfile = optarg;
+		case 'T':
+			options.trim_whitespace = true;
 			break;
-		case 'd':
-			Options.depth = strtoul(optarg, NULL, 0);
+		case 'I':
+			options.interleave = true;
+			break;
+		case 'D':
+			options.remove_duplicates = true;
+			break;
+		case 'W':
+			options.keep_whitespace = true;
+			break;
+		case 'X':
+			options.remove_xflip = true;
+			break;
+		case 'Y':
+			options.remove_yflip = true;
 			break;
 		case 'r':
-			token = strtok(optarg, ",");
-			while (token) {
-				Options.num_preserved++;
-				Options.preserved = realloc(Options.preserved, Options.num_preserved * sizeof(int));
-				Options.preserved[Options.num_preserved-1] = strtoul(token, NULL, 0);
-				token = strtok(NULL, ",");
+			for (char *token = strtok(optarg, ","); token; token = strtok(NULL, ",")) {
+				options.preserved = xrealloc(options.preserved, ++options.num_preserved * sizeof(*options.preserved));
+				options.preserved[options.num_preserved-1] = strtoul(token, NULL, 0);
 			}
 			break;
-		case 'p':
-			Options.png_file = optarg;
+		case 'd':
+			options.depth = strtoul(optarg, NULL, 0);
 			break;
-		case 0:
-		case -1:
+		case 'p':
+			options.png_file = optarg;
+			break;
+		case 'o':
+			options.outfile = optarg;
+			break;
+		case 'h':
+			usage_exit(0);
 			break;
 		default:
-			usage();
-			exit(1);
-			break;
+			usage_exit(1);
 		}
 	}
 }
 
+struct Graphic {
+	uint8_t *data;
+	long size;
+};
+
 bool is_preserved(int index) {
-	for (int i = 0; i < Options.num_preserved; i++) {
-		if (Options.preserved[i] == index) {
+	for (int i = 0; i < options.num_preserved; i++) {
+		if (options.preserved[i] == index) {
 			return true;
 		}
 	}
@@ -96,22 +98,16 @@ bool is_preserved(int index) {
 }
 
 void shift_preserved(int removed_index) {
-	for (int i = 0; i < Options.num_preserved; i++) {
-		if (Options.preserved[i] >= removed_index) {
-			Options.preserved[i]--;
+	for (int i = 0; i < options.num_preserved; i++) {
+		if (options.preserved[i] >= removed_index) {
+			options.preserved[i]--;
 		}
 	}
 }
 
-struct Graphic {
-	int size;
-	uint8_t *data;
-};
-
-bool is_whitespace(uint8_t *tile, int tile_size) {
-	uint8_t WHITESPACE = 0;
+bool is_whitespace(const uint8_t *tile, int tile_size) {
 	for (int i = 0; i < tile_size; i++) {
-		if (tile[i] != WHITESPACE) {
+		if (tile[i] != 0) {
 			return false;
 		}
 	}
@@ -119,7 +115,7 @@ bool is_whitespace(uint8_t *tile, int tile_size) {
 }
 
 void trim_whitespace(struct Graphic *graphic) {
-	int tile_size = Options.depth * 8;
+	int tile_size = options.depth * 8;
 	for (int i = graphic->size - tile_size; i > 0; i -= tile_size) {
 		if (is_whitespace(&graphic->data[i], tile_size) && !is_preserved(i / tile_size)) {
 			graphic->size = i;
@@ -129,36 +125,34 @@ void trim_whitespace(struct Graphic *graphic) {
 	}
 }
 
+int get_tile_size(void) {
+	return options.depth * (options.interleave ? 16 : 8);
+}
+
 void remove_whitespace(struct Graphic *graphic) {
-	int tile_size = Options.depth * 8;
-	if (Options.interleave) tile_size *= 2;
-	
-	// Make sure we have a whole number of tiles, round down if required
+	int tile_size = get_tile_size();
 	graphic->size &= ~(tile_size - 1);
-	
 	int i = 0;
 	for (int j = 0, d = 0; i < graphic->size && j < graphic->size; i += tile_size, j += tile_size) {
-		while (j < graphic->size && is_whitespace(&graphic->data[j], tile_size) && !is_preserved(j / tile_size - d)) {
+		for (; j < graphic->size && is_whitespace(&graphic->data[j], tile_size) && !is_preserved(j / tile_size - d); j += tile_size, d++) {
 			shift_preserved(j / tile_size - d);
-			d++;
-			j += tile_size;
 		}
 		if (j >= graphic->size) {
 			break;
-		}
-		if (j > i) {
+		} else if (j > i) {
 			memcpy(&graphic->data[i], &graphic->data[j], tile_size);
 		}
 	}
 	graphic->size = i;
 }
 
-bool tile_exists(uint8_t *tile, uint8_t *tiles, int tile_size, int num_tiles) {
+bool tile_exists(const uint8_t *tile, const uint8_t *tiles, int tile_size, int num_tiles) {
 	for (int i = 0; i < num_tiles; i++) {
 		bool match = true;
 		for (int j = 0; j < tile_size; j++) {
 			if (tile[j] != tiles[i * tile_size + j]) {
 				match = false;
+				break;
 			}
 		}
 		if (match) {
@@ -169,21 +163,15 @@ bool tile_exists(uint8_t *tile, uint8_t *tiles, int tile_size, int num_tiles) {
 }
 
 void remove_duplicates(struct Graphic *graphic) {
-	int tile_size = Options.depth * 8;
-	if (Options.interleave) tile_size *= 2;
-	int num_tiles = 0;
-	
-	// Make sure we have a whole number of tiles, round down if required
+	int tile_size = get_tile_size();
 	graphic->size &= ~(tile_size - 1);
-	
+	int num_tiles = 0;
 	for (int i = 0, j = 0, d = 0; i < graphic->size && j < graphic->size; i += tile_size, j += tile_size) {
-		while (j < graphic->size && tile_exists(&graphic->data[j], graphic->data, tile_size, num_tiles)) {
-			if ((Options.keep_whitespace && is_whitespace(&graphic->data[j], tile_size)) || is_preserved(j / tile_size - d)) {
+		for (; j < graphic->size && tile_exists(&graphic->data[j], graphic->data, tile_size, num_tiles); j += tile_size, d++) {
+			if ((options.keep_whitespace && is_whitespace(&graphic->data[j], tile_size)) || is_preserved(j / tile_size - d)) {
 				break;
 			}
 			shift_preserved(j / tile_size - d);
-			d++;
-			j += tile_size;
 		}
 		if (j >= graphic->size) {
 			break;
@@ -196,48 +184,49 @@ void remove_duplicates(struct Graphic *graphic) {
 	graphic->size = num_tiles * tile_size;
 }
 
-bool flip_exists(uint8_t *tile, uint8_t *tiles, int tile_size, int num_tiles, bool xflip, bool yflip) {
-	uint8_t flip[tile_size];
-	memset(flip, 0, sizeof(flip));
+// for (int i = 0; i < 256; i++)
+//	for (int bit = 0; bit < 8; bit++) {
+//		flipped[i] |= ((i >> bit) & 1) << (7 - bit);
+const uint8_t flipped[256] = {
+	0x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0, 0x10, 0x90, 0x50, 0xd0, 0x30, 0xb0, 0x70, 0xf0,
+	0x08, 0x88, 0x48, 0xc8, 0x28, 0xa8, 0x68, 0xe8, 0x18, 0x98, 0x58, 0xd8, 0x38, 0xb8, 0x78, 0xf8,
+	0x04, 0x84, 0x44, 0xc4, 0x24, 0xa4, 0x64, 0xe4, 0x14, 0x94, 0x54, 0xd4, 0x34, 0xb4, 0x74, 0xf4,
+	0x0c, 0x8c, 0x4c, 0xcc, 0x2c, 0xac, 0x6c, 0xec, 0x1c, 0x9c, 0x5c, 0xdc, 0x3c, 0xbc, 0x7c, 0xfc,
+	0x02, 0x82, 0x42, 0xc2, 0x22, 0xa2, 0x62, 0xe2, 0x12, 0x92, 0x52, 0xd2, 0x32, 0xb2, 0x72, 0xf2,
+	0x0a, 0x8a, 0x4a, 0xca, 0x2a, 0xaa, 0x6a, 0xea, 0x1a, 0x9a, 0x5a, 0xda, 0x3a, 0xba, 0x7a, 0xfa,
+	0x06, 0x86, 0x46, 0xc6, 0x26, 0xa6, 0x66, 0xe6, 0x16, 0x96, 0x56, 0xd6, 0x36, 0xb6, 0x76, 0xf6,
+	0x0e, 0x8e, 0x4e, 0xce, 0x2e, 0xae, 0x6e, 0xee, 0x1e, 0x9e, 0x5e, 0xde, 0x3e, 0xbe, 0x7e, 0xfe,
+	0x01, 0x81, 0x41, 0xc1, 0x21, 0xa1, 0x61, 0xe1, 0x11, 0x91, 0x51, 0xd1, 0x31, 0xb1, 0x71, 0xf1,
+	0x09, 0x89, 0x49, 0xc9, 0x29, 0xa9, 0x69, 0xe9, 0x19, 0x99, 0x59, 0xd9, 0x39, 0xb9, 0x79, 0xf9,
+	0x05, 0x85, 0x45, 0xc5, 0x25, 0xa5, 0x65, 0xe5, 0x15, 0x95, 0x55, 0xd5, 0x35, 0xb5, 0x75, 0xf5,
+	0x0d, 0x8d, 0x4d, 0xcd, 0x2d, 0xad, 0x6d, 0xed, 0x1d, 0x9d, 0x5d, 0xdd, 0x3d, 0xbd, 0x7d, 0xfd,
+	0x03, 0x83, 0x43, 0xc3, 0x23, 0xa3, 0x63, 0xe3, 0x13, 0x93, 0x53, 0xd3, 0x33, 0xb3, 0x73, 0xf3,
+	0x0b, 0x8b, 0x4b, 0xcb, 0x2b, 0xab, 0x6b, 0xeb, 0x1b, 0x9b, 0x5b, 0xdb, 0x3b, 0xbb, 0x7b, 0xfb,
+	0x07, 0x87, 0x47, 0xc7, 0x27, 0xa7, 0x67, 0xe7, 0x17, 0x97, 0x57, 0xd7, 0x37, 0xb7, 0x77, 0xf7,
+	0x0f, 0x8f, 0x4f, 0xcf, 0x2f, 0xaf, 0x6f, 0xef, 0x1f, 0x9f, 0x5f, 0xdf, 0x3f, 0xbf, 0x7f, 0xff
+};
+
+bool flip_exists(const uint8_t *tile, const uint8_t *tiles, int tile_size, int num_tiles, bool xflip, bool yflip) {
+	uint8_t flip[tile_size]; // VLA
+	memset(flip, 0, tile_size);
 	int half_size = tile_size / 2;
 	for (int i = 0; i < tile_size; i++) {
-		int byte = i;
-		if (yflip) {
-			byte = tile_size - 1 - (i ^ 1);
-			if (Options.interleave && i < half_size) {
-				byte = half_size - 1 - (i ^ 1);
-			}
-		}
-		if (xflip) {
-			for (int bit = 0; bit < 8; bit++) {
-				flip[byte] |= ((tile[i] >> bit) & 1) << (7 - bit);
-			}
-		} else {
-			flip[byte] = tile[i];
-		}
+		int j = yflip ? (options.interleave && i < half_size ? half_size : tile_size) - 1 - (i ^ 1) : i;
+		flip[j] = xflip ? flipped[tile[i]] : tile[i];
 	}
-	if (tile_exists(flip, tiles, tile_size, num_tiles)) {
-		return true;
-	}
-	return false;
+	return tile_exists(flip, tiles, tile_size, num_tiles);
 }
 
 void remove_flip(struct Graphic *graphic, bool xflip, bool yflip) {
-	int tile_size = Options.depth * 8;
-	if (Options.interleave) tile_size *= 2;
-	int num_tiles = 0;
-	
-	// Make sure we have a whole number of tiles, round down if required
+	int tile_size = get_tile_size();
 	graphic->size &= ~(tile_size - 1);
-	
+	int num_tiles = 0;
 	for (int i = 0, j = 0, d = 0; i < graphic->size && j < graphic->size; i += tile_size, j += tile_size) {
-		while (j < graphic->size && flip_exists(&graphic->data[j], graphic->data, tile_size, num_tiles, xflip, yflip)) {
-			if ((Options.keep_whitespace && is_whitespace(&graphic->data[j], tile_size)) || is_preserved(j / tile_size - d)) {
+		for (; j < graphic->size && flip_exists(&graphic->data[j], graphic->data, tile_size, num_tiles, xflip, yflip); j += tile_size, d++) {
+			if ((options.keep_whitespace && is_whitespace(&graphic->data[j], tile_size)) || is_preserved(j / tile_size - d)) {
 				break;
 			}
 			shift_preserved(j / tile_size - d);
-			d++;
-			j += tile_size;
 		}
 		if (j >= graphic->size) {
 			break;
@@ -251,18 +240,13 @@ void remove_flip(struct Graphic *graphic, bool xflip, bool yflip) {
 }
 
 void interleave(struct Graphic *graphic, int width) {
-	int tile_size = Options.depth * 8;
+	int tile_size = options.depth * 8;
 	int width_tiles = width / 8;
 	int num_tiles = graphic->size / tile_size;
-	uint8_t *interleaved = malloc(graphic->size);
+	uint8_t *interleaved = xmalloc(graphic->size);
 	for (int i = 0; i < num_tiles; i++) {
-		int tile = i * 2;
 		int row = i / width_tiles;
-		tile -= width_tiles * row;
-		if (row % 2) {
-			tile -= width_tiles;
-			tile += 1;
-		}
+		int tile = i * 2 - (row % 2 ? width_tiles * (row + 1) - 1 : width_tiles * row);
 		memcpy(&interleaved[tile * tile_size], &graphic->data[i * tile_size], tile_size);
 	}
 	graphic->size = num_tiles * tile_size;
@@ -270,76 +254,47 @@ void interleave(struct Graphic *graphic, int width) {
 	free(interleaved);
 }
 
-int png_get_width(char *filename) {
-	FILE *f = fopen_verbose(filename, "rb");
-	if (!f) {
-		exit(1);
-	}
-
-	const int OFFSET_WIDTH = 16;
-	uint8_t bytes[4];
-	fseek(f, OFFSET_WIDTH, SEEK_SET);
-	size_t size = 4;
-	size_t result = fread(bytes, 1, size, f);
-	fclose(f);
-	if (result != size) {
-		fprintf(stderr, "Could not read file at offset 0x%x: \"%s\"\n", OFFSET_WIDTH, filename);
-		exit(1);
-	}
-
-	int width = 0;
-	for (int i = 0; i < 4; i++) {
-		width |= bytes[i] << (8 * (3 - i));
-	}
-	return width;
-}
-
-
 int main(int argc, char *argv[]) {
-	get_args(argc, argv);
+	parse_args(argc, argv);
+
 	argc -= optind;
 	argv += optind;
-	if (Options.help) {
-		usage();
-		return 0;
-	}
 	if (argc < 1) {
-		usage();
-		exit(1);
+		usage_exit(1);
 	}
-	char *infile = argv[0];
+
 	struct Graphic graphic;
-	graphic.data = read_u8(infile, &graphic.size);
-	if (Options.trim_whitespace) {
+	graphic.data = read_u8(argv[0], &graphic.size);
+
+	if (options.trim_whitespace) {
 		trim_whitespace(&graphic);
 	}
-	if (Options.interleave) {
-		if (!Options.png_file) {
-			error("interleave: need --png to infer dimensions");
-			usage();
-			exit(1);
+	if (options.interleave) {
+		if (!options.png_file) {
+			error_exit("--interleave needs --png to infer dimensions");
 		}
-		int width = png_get_width(Options.png_file);
+		int width = read_png_width(options.png_file);
 		interleave(&graphic, width);
 	}
-	if (Options.remove_duplicates) {
+	if (options.remove_duplicates) {
 		remove_duplicates(&graphic);
 	}
-	if (Options.remove_xflip) {
+	if (options.remove_xflip) {
 		remove_flip(&graphic, true, false);
 	}
-	if (Options.remove_yflip) {
+	if (options.remove_yflip) {
 		remove_flip(&graphic, false, true);
 	}
-	if (Options.remove_xflip && Options.remove_yflip) {
+	if (options.remove_xflip && options.remove_yflip) {
 		remove_flip(&graphic, true, true);
 	}
-	if (Options.remove_whitespace) {
+	if (options.remove_whitespace) {
 		remove_whitespace(&graphic);
 	}
-	if (Options.outfile) {
-		write_u8(Options.outfile, graphic.data, graphic.size);
+	if (options.outfile) {
+		write_u8(options.outfile, graphic.data, graphic.size);
 	}
+
 	free(graphic.data);
 	return 0;
 }
diff --git a/tools/scan_includes.c b/tools/scan_includes.c
index 63af3bcf..e57ddc35 100644
--- a/tools/scan_includes.c
+++ b/tools/scan_includes.c
@@ -1,135 +1,98 @@
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <stdbool.h>
-#include <getopt.h>
+#define PROGRAM_NAME "scan_includes"
+#define USAGE_OPTS "[-h|--help] [-s|--strict] filename.asm"
 
-void usage(void) {
-	printf("Usage: scan_includes [-h] [-s] filename\n"
-	       "-h, --help\n"
-	       "    Print usage and exit\n"
-	       "-s, --strict\n"
-	       "    Fail if a file cannot be read\n");
-}
+#include "common.h"
 
-struct Options {
-	bool help;
-	bool strict;
-};
-
-struct Options Options = {0};
-
-void scan_file(char* filename) {
-	FILE *f = fopen(filename, "rb");
-	if (!f) {
-		if (Options.strict) {
-			fprintf(stderr, "Could not open file: '%s'\n", filename);
-			exit(1);
-		} else {
-			return;
-		}
-	}
-
-	fseek(f, 0, SEEK_END);
-	long size = ftell(f);
-	rewind(f);
-
-	char *buffer = malloc(size + 1);
-	char *orig = buffer;
-	size = fread(buffer, 1, size, f);
-	buffer[size] = '\0';
-	fclose(f);
-
-	for (; buffer && (buffer - orig < size); buffer++) {
-		bool is_include = false;
-		bool is_incbin = false;
-		switch (*buffer) {
-			case ';':
-				buffer = strchr(buffer, '\n');
-				if (!buffer) {
-					fprintf(stderr, "%s: no newline at end of file\n", filename);
-					break;
-				}
-				break;
-
-			case '"':
-				buffer++;
-				buffer = strchr(buffer, '"');
-				if (!buffer) {
-					fprintf(stderr, "%s: unterminated string\n", filename);
-					break;
-				}
-				buffer++;
-				break;
-
-			case 'i':
-			case 'I':
-				if ((strncmp(buffer, "INCBIN", 6) == 0) || (strncmp(buffer, "incbin", 6) == 0)) {
-					is_incbin = true;
-				} else if ((strncmp(buffer, "INCLUDE", 7) == 0) || (strncmp(buffer, "include", 7) == 0)) {
-					is_include = true;
-				}
-				if (is_incbin || is_include) {
-					buffer = strchr(buffer, '"');
-					if (!buffer) {
-						break;
-					}
-					buffer++;
-					int length = strcspn(buffer, "\"");
-					char *include = malloc(length + 1);
-					strncpy(include, buffer, length);
-					include[length] = '\0';
-					printf("%s ", include);
-					if (is_include) {
-						scan_file(include);
-					}
-					free(include);
-					buffer = strchr(buffer, '"');
-				}
-				break;
-
-		}
-		if (!buffer) {
-			break;
-		}
-
-	}
-
-	free(orig);
-}
-
-int main(int argc, char* argv[]) {
-	int i = 0;
+void parse_args(int argc, char *argv[], bool *strict) {
 	struct option long_options[] = {
 		{"strict", no_argument, 0, 's'},
 		{"help", no_argument, 0, 'h'},
 		{0}
 	};
-	int opt = -1;
-	while ((opt = getopt_long(argc, argv, "sh", long_options, &i)) != -1) {
+	for (int opt; (opt = getopt_long(argc, argv, "sh", long_options)) != -1;) {
 		switch (opt) {
 		case 's':
-			Options.strict = true;
+			*strict = true;
 			break;
 		case 'h':
-			Options.help = true;
+			usage_exit(0);
 			break;
 		default:
-			usage();
-			exit(1);
+			usage_exit(1);
+		}
+	}
+}
+
+void scan_file(const char *filename, bool strict) {
+	errno = 0;
+	FILE *f = fopen(filename, "rb");
+	if (!f) {
+		if (strict) {
+			error_exit("Could not open file \"%s\": %s\n", filename, strerror(errno));
+		} else {
+			return;
+		}
+	}
+
+	long size = xfsize(filename, f);
+	char *contents = xmalloc(size + 1);
+	xfread((uint8_t *)contents, size, filename, f);
+	fclose(f);
+	contents[size] = '\0';
+
+	for (char *ptr = contents; ptr && ptr - contents < size; ptr++) {
+		bool is_incbin = false, is_include = false;
+		switch (*ptr) {
+		case ';':
+			ptr = strchr(ptr, '\n');
+			if (!ptr) {
+				fprintf(stderr, "%s: no newline at end of file\n", filename);
+			}
+			break;
+		case '"':
+			ptr++;
+			ptr = strchr(ptr, '"');
+			if (ptr) {
+				ptr++;
+			} else {
+				fprintf(stderr, "%s: unterminated string\n", filename);
+			}
+			break;
+		case 'I':
+		case 'i':
+			is_incbin = !strncmp(ptr, "INCBIN", 6) || !strncmp(ptr, "incbin", 6);
+			is_include = !strncmp(ptr, "INCLUDE", 7) || !strncmp(ptr, "include", 7);
+			if (is_incbin || is_include) {
+				ptr = strchr(ptr, '"');
+				if (ptr) {
+					ptr++;
+					char *include_path = ptr;
+					size_t length = strcspn(ptr, "\"");
+					ptr += length + 1;
+					include_path[length] = '\0';
+					printf("%s ", include_path);
+					if (is_include) {
+						scan_file(include_path, strict);
+					}
+				}
+			}
 			break;
 		}
 	}
+
+	free(contents);
+}
+
+int main(int argc, char *argv[]) {
+	bool strict = false;
+	parse_args(argc, argv, &strict);
+
 	argc -= optind;
 	argv += optind;
-	if (Options.help) {
-		usage();
-		return 0;
-	}
 	if (argc < 1) {
-		usage();
-		exit(1);
+		usage_exit(1);
 	}
-	scan_file(argv[0]);
+
+	scan_file(argv[0], strict);
 	return 0;
 }